Musköloppet is a summer running event held on Muskö, starting and finishing at Muskö Hembygdsgård near Muskö IF's clubhouse. Approximately 300 runners participate in the main races, increasing to around 400 when the youngest children's races are included. The event includes races for children and youth, a 5 km run, a 10 km run, and a 3 x approximately 1 km relay, allowing families with participants of different ages to compete on the same day.
The 5 km and 10 km courses are officially measured and traverse varied terrain within an archipelago landscape. The event also serves as a local gathering: many use race day to reconnect with relatives, neighbors, and friends, with food and coffee available at the start and finish area. Musköloppet celebrated its 30th anniversary following a pandemic postponement, highlighting its significance in the Muskö community calendar.